Preparation and properties of fluorosilicone composites with thermal conductivity and chemical resistance through modification of filler and matrix

Abstract

The improvement of heat dissipation and chemical resistance of encapsulating materials can greatly increase the service life of electronic devices. Fluorosilicone rubber exhibits superior chemical resistance compared to silicone rubber when used for encapsulation, enabling it to effectively handle highly complex application scenarios. In this study, a thermally conductive and chemically resistant composite material (i.e., F-Al2O3/F-AlN@F-ALSR) was prepared by introducing fluorine-modified Al2O3 and AlN into fluorine-added liquid silicone rubber matrix from both filler and matrix fluorination modification perspectives. The effects of the properties of fillers before and after modification, different mixing ratios (i.e., the ratio of F-Al2O3 to F-AlN) and different addition amounts (i.e., the amount of F-Al2O3/F-AlN added in F-ALSR) on the thermal conductivity and chemical medium resistance of the composite material were investigated, and the mechanisms of thermal conductivity and chemical medium resistance were explored. The results showed that when the ratio of F-Al2O3 to F-AlN was 3:7 and the total amount of filling was 300 phr, the material had a thermal conductivity of 1.047 W/mK and a thermal diffusivity of 0.652 mm2/s. The rate of change of mass and volume during 72 h of immersion in acid, alkali, toluene and engine oil was low. This further proves that the addition of F-Al2O3/F-AlN in F-ALSR can effectively create a heat conduction path and protect the composite material from environmental effects, resulting in materials with excellent thermal conductivity and chemical resistance. This study provides new ideas for improving the dispersion of fillers in the matrix and rationalizing the preparation of liquid silicone rubbers for thermally conductive, chemically resistant electronic potting.